Plastic packaging for exhibiting a wide variety of articles are well-known and various arrangements are known to secure the packages closed. For example, U.S. Pat. No. 3,786,932 to Rakes et al, issued Jan. 22, 1974; U.S. Pat. No. 4,512,474 to Harding, issued Apr. 23, 1985 and U.S. Pat. No. 4,576,330 to Schepp, issued Mar. 18, 1986 all show plastic packaging and locking arrangements in which male elements are received in forcefit or snap engagement within a female element. The arrangement of Rakes, Harding and Schepp all suffer the disadvantage that it is difficult to form the male and female elements so as to have a resiliency to permit snap lock insertion of the male element into the female element and provide the male and female elements with sufficient strength to avoid crushing of the male or female elements during a manual closing operation in which finger and/or thumb pressure is applied to the axial end of male and female elements. This disadvantage is recognized by U.S. Pat. No. 4,771,934 to Kalmandies, issued Sep. 20, 1988 which proposes, as a solution, the protection of an upstanding female element from crushing by providing protective upstanding lands on either side of a female element. Kalmandies has a disadvantage of requiring a more complex mould and of having a structure which is not readily adapted for closing by automated machines.
The male and female arrangements taught by Harding, Schepp and Kalmandies all utilize male elements with enlarged head portions. These enlarged head portions have the disadvantage that they are difficult to manufacture. None of these patents disclose a practical method of manufacturing the male element to provide a consistently formed enlarged head portion.